1. Contour line
The intersection of ground surface and level surface is called contour line.
2. Contour interval
The perpendicular distance between two successive contours is known as contour interval.
3. Horizontal equivalent
The horizontal distance between two successive contours is known as horizontal equivalent
Objects of contouring:
In engineering projects knowledge of contouring is important for determining nature of ground surface.
Uses of contour maps
- Ground surface is examined by it.
- Its widely used in site selection.
- Storage power of reservoir is calculated.
- Two distinct stations are visible or not is determined.
- Catchment can be determined by drawing in any direction.
Characteristics of contours
- At top of hills contour lines are near to each other.
- If contour lines are equally spaced it represents a uniform slope.
- Contour lines never meet each one another.
- Contours that are close to each other represents depressions.
- Depression between summits is called saddles.
Methods of contouring
There are two methods of contouring
1. Direct method.
2. Method of interpolation.
3. Indirect method.